Zig-zag sewing machine



Aug. 17, 1965 A. H. ERIKSSON 3,200,780

ZIG-ZAG SEWING MACHINE Filed June 22, 1962 United States Patent 3,2tlilfiilti ZlG-ZAG SEWlNG MACHENE Allan Herman Erilrsson, Elrhem, Hushvarna, Sweden, assignor to Husgvarna Vapenfahrihs Alrtieholag, Hushvarna, weden Filed June 22, 1962, Ser. No. 284,474 maims priority, application Sweden, .iuly E5, 1961, 6,392/ s1 4 Qlainis. ((11. 112-458) This invention relates to sewing machines, particularly to sewing machines having a working-member with a variable reciprocating motion, such as a laterally swingable needle-bar hearing of a zigzag sewing machine.

The invention has for its object to provide a simple, cheap and reliable driving device for such a working member of a sewing machine.

Another object of the invention is to provide, in zigzag sewing machines, a very simple device for changing the stitch field or the starting position of the zigzag seam. According to the invention the starting position and the seam width can advantageously be changed by two different manipulations of one and the same handle, preferably an axial displacement and a turning thereof, respectively. By simple means also a semi-automatic production of buttonhole seams is here made possible.

With the above and other objects in View, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawing of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

in the accompanying drawing which shows pertinent parts of a domestic zigzag sewing machine according to the invention, PEG. 1 is a vertical longitudinal section through the top of the machine, FIG. 2 is a section on line ll-ll in FIG. 1, FIGS. 3 and 4 are sections on lines llllll and lVlV, respectively, in FIG. 2, FlG. 5 is a section on line V V in FIG. 3, FIG. 6 is a plane evolution of a cam body, FIG. 7 is a plan view of this cam body with follower, the latter partly in section, FIG. 8 is a seam representation and PEG. 9 is a perspective view of a handle for regulating the width and the stitch held of the zigzag seam. FIGS. 1, 2 and 6 are on a smaller scale than the rest of the figures.

The machine shown has a hollow frame ill with a sewarm 11, a longitudinal drive shaft 12 journalled therein, and a bearing 13 for a longitudinally and vertically movable needle-bar l twith a sewing needle 15. The bearing 13 is swingable laterally about a horizontal pin 16 at the free end of the sew-arm. The shaft 12 has a belt pulley 1'7 which is driven from an electric motor, not shown, and drives the needle-bar by means of a crank mechanism 18 known per se. A frame base, not shown, situated under the sew-arm and supporting the work horizontally, contains a thread loop-taker cooperating with the needle to produce lock stitches, and a work feeder operative perpendicularly to a vertical plane through shaft 12 and having a substantially rectangular path of movement. So far the machine may be of a well-known design which need not be more closely described here.

A driving device for the laterally movable needle-bar bearing 13 comprises a substantially cylindrical cam body Ztl fixed on the drive shaft 12 and having a peripheral groove 21 which comprises two turns and which, according to PEG. 6, crosses itself at a point 22 in a cross-over part 23 between the ends of two groove-parts 24, 25 perpendicular to the direction of shaft 12. The sides of the groove converge towards its bottom, the groove having Cir in cross-section the shape of a trapezoid, more particularly a truncate isosceles triangle. A corresponding crosssection has at its middle an arcuate follower 26 tapering towards its ends and engaging the groove without touching its bottom, said follower having a horizontal pivot 27 which is perpendicular to the drive shaft 12 and is swingably but not slidably journalled in the free, upper end of a swing-arm 28 on a horizontal axle 29 which is parallel to pin 27 and swingably but not slidably journalled in a bushing 3i fixedly mounted in the sew-arm. Provided in the arm 28 is a slide-guide 31 for a guidefollower in the shape of a roll 32 on one end of a connecting rod 33 the other end of which is, by means of a hinge 34, connected to the needle-bar bearing 13 which is biased to the left in HS. 1 by a leaf-spring 35 secured to the sew-arm. The guide 31 is approximately perpendicuiar to a line through the hinge 34 and the center of roll 32 when the groove follower 26 is at the cross-point 22. Near the roll 32 the rod 33 has a substantially horizontal slot 36 for a roll 37 on the free end of a pin 33 projecting from a crank 39 on a setting shaft dd extending parallel to axle 29, shaft ill being turnably and axially slidably iournalled in the sew-arm H and extending tlnough its front wall. Joining the front: side of the latter is a dial disk ii which is concentric to and turnable together with shaft 4@ but not axially displaceable, said disk having a numerical scale 42 and a cylindrical part 43 partly situated in a cylindrical part 44 of a knob 45 fixed to shaft By the act of turning this knob the roll 32 is adjustable in the slide-guide 31 between a lower position 56 wherein the roll is coaxial with the pivot 29 of arm 23, and the position d7 shown in FIG. 3, at the upper end of the slide-guide. Upon rotation of drive shaft 12 an oscillating motion is imparted to arm 28, the magnitude of which motion depends on the mutual axial distance of the groove-parts 2d, 25 and which motion is transmitted to the needle-bar bearing 13 by the rod 33 when roll 32 is above position to. The length of the groove-parts 24, 25 and their pheripheral position relative to the crank mechanism 18, is such that the groove follower 26 is alternately situated in these parts and the bearing 13 is consequently at rest when the needle is situated in the fabric. The length of slide-guide 31 and the distance between the parts 16 and 34 is such that a zigzag seam of the desired maximum width, say 4 millimeters, is obtained when roll 32 is set in position 47, every second stitch occurring in position L to the left of a middle position M for the needle, and the other stitches occurring in a position R equally much to the right of position M, FIG. If the distance of the roll from position 46 is reduced, one obtains a zigzag seam a of a correspondingly reduced width but with unchanged middle position M. in position id the stitch width is naught and one thus obtains a straight seam b in position M. The numerals of scale 42 indicate the stitch width in millimeters when they, by means of knob 45, are set opposite a fixe index 48 on the front side of the sew-arm.

For the purpose of changing the starting position of the zigzag seam (the stitch field) the arm 23 is also provided with two single-sided slide-guides 5d, 51 which are open towards the bearing 13 and with either of which the roll 32. can be brouhgt into contact under the pressure of spring 35, said guides diverging from position 47 towards the pivot of the arm in such a way that the roll 32, when engaging the slide-guides 5th and 51 in its lower end position, is situated with its center so far to the left and to the right of position as, respectively, that the needle is in position L, R, respectively, and a straight seam c, d, respectively, is obtained. When the roll is set in its upper end position by means of the knob 45, one still obtains a zigzag seam with stitches in positions L and R. In intermediate positions of the roll one obtains a zigzag seam e, f, respecively, of less width and with every second stitch in position L, R, respectively, that is to say a zigzag seam with the left or the right starting position, respectively. In its upper end position roll 32 is axially slidable from one to another of the slide-guides 31, t and 51 by displacing the knob 45, the hinge 34 being adapted to permit the necessary lateral swinging of connecting rod 33 which is engaged between pin 38 and a flange 52 on rod 37. The axial displacement, just mentioned, of roll 32 should bring no noteworthy lateral displacement of the needle. If the horizontally somewhat swingable connecting rod 33 is relatively short, this may call for a slight modification of the mutual lateral positions of the slide-guides so that they will no longer coincide at their tops. The axial displacement of the roll can in such case be provided for by rounding off or chamfering the edges of the roll. The dial part 43 has three symbols 53 for the middle, the left and the right starting positions, respectively, which symbols are situated in a recess 54 in knob part 44 when the slide-guide 31, 5t and 51, respectively, is in engagement with roll 32. At these instances an arcuate part 55 of a spring-actuated arm 56 hingedly mounted on arm 39, which part is substantially concentric to setting shaft 40, engages one of three grooves 57 in bushing so as to arrest the setting shaft and the knob in corresponding, axial positions. At a displacement of the setting shaft from such a position, the arm part 55 yields only in the direction towards the setting shaft. For arresting the knob in the angular position wherein it has been set, a friction brake can be used, preferably in the shape of a resilient, in unstrained condition somewhat curved sheet metal disk 58 confined on the setting shaft against the arm 39, said disk straddling the bushing 35 with a pair of legs 59 and being thereby prevented from turning together with shaft 40. For the purpose of coordinating the angular position of dial disk 41 and the level of roll 32 the roll 37 can be adjustable as to its angular position upon an eccentric pin as on pin 38.

For producing a usual buttonhole seam comprising a zigzag seam at each side of the button hole and a wider bar at each end thereof, one can first set the machine for backward feed with a small stitch length and, by means of knob 45, for the left starting position and the seam width two millimeters. With these adjustments the zigzag seam to the left of the buttonhole in being is produced. After this scam has obtained the desired length, the machine is set for forward feed with unchanged stitch length, which setting is maintained during the remaining r sewing operations, and knob is set for the right starting position, which is also maintained during the remaining sewing operations, and for the seam width 4 millimeters. With these settings one of the bars is produced After the seam width has been reduced to 2 millimeters, the zigzag seam to the right of the buttonhole is obtained. Thereupon the seam width 4 millimeters is again set for the purpose of sewing the second bar. After setting the seam width 0 some straight fastening stitches may be produced in the right starting position (R). In order to facilitate the handling of the knob when sewing buttonholes the arm part may, at one or more of the points which engage a groove 57 in the used angular positions of the knob, for instance for the seam width 2 millimeters, be provided with a shallow recess at reducing the turning resistance of the knob so that one immediately feels when the angular position in question has been reached.

The cam body consists of a material having a lower casting temperature and better sound-deadening properties than massive iron and is shaped in a shaping tool, such as a metal press casting tool in which case the cam body may consist of a known-press-casting metal, such as as nylon or acetal plastic, delrin) in which case the groove follower may be of nylon. The shaping is substantially facilitated by the cross-sectional shape of the cam groove which narrows towards its bottom, which cross-sectional shape has also proved to give a relatively silent run and to facilitate switching in the cross-over part 23. The shaping in a shaping tool can cause an unnecessary large lateral playin the groove. The disadvantage thereof is eliminated, however, by providing that the follower normally engages one side of the groove under the pressure of spring 13. This one also makes possible the open or single-sided design of the slide-guides 50, 51 which facilitates a shaping in a shaping tool also of the parts 28, 29, preferably in one piece of plastic. Also the parts 30 and 56 are preferably of plastic (nylon).

A driving device according to the invention can also be used, for instance, for producing the longitudinal movements of the fabric feeder or the lateral movements of a fabric feeder which is movable also laterally. Optionally, the cam body can be a rotary disk in which case the groove is provided in one side of the disk and acts radial- 1y instead of axially.

What is claimed is:

1. A zigzag sewing machine having a hollow frame, a drive shaft journalled in said frame, a longitudinally reciprocable and laterally swingable needle-bar carried by said frame, exterior handle means on said frame, and a device within said frame for imparting a variable lateral motion to said needle-bar, said device comprising a cam driven by said shaft, a swing-arm driven by said cam and having a pivot axle and a pluarlity of adjacent, alternative slide-guides which diverge towards the pivot axle of said swing-arm from a transfer position at a distance therefrom and in a plane perpendicular to said axle, and a guide follower connected to said needle-bar and adjustable along any of said slide-guides for varying the amplitude of the swinging motion of the needle-bar and adjustable in the direction of said pivot axle when in said transfer position selectively between said slide-guides for changing the field position of said swinging motion, said guide follower being operatively connected with, and adjustable and transferable by said exterior handle means.

2. A zigzag sewing machine according to claim 1, comprising a turnable and longitudinally movable setting shaft extending parallel to said pivot axle through a wall of said frame and having an outer end, and setting motion transmitting means interconnecting said shaft and said guide follower, said setting motion transmitting means being adapted to move said guide follower together with said shaft in the direction of said pivot axle and to adjust said guide follower along any of said slide-guides according to the angular position of said shaft, said handle means being a single handle on the outer end of said setting shaft.

3. A zigzag sewing machine comprising a hollow frame, first adjustable control means in said frame for controlling the width of a zig-zag seam, second adjustable control means in said frame for controlling the stitch field position, and a revolvable handle carried by said frame and capable of being set and arrested in different axial positions and in different angular positions in each of said axial positions, said two control means being operatively connected with said handle so as to be adjustable, one of them by setting said handle axially and the other by turning said handle.

4. A sewing machine comprising a hollow frame, first and second adjustable stitch control means in said frame, a revolvable handle carried by said frame and capable of being set in different axial positions and in different angular positions in each of said axial positions, yieldable arresting means associated with said handle for keeping it in any set position, and setting motion transmitting means interconnecting said handle and said two stitch control means, said first stitch control means being adjustable by turning said handle to any axial position there- 5 6 of, and said second stitch control means being adjustable 2,515,342 7/50 Glaser 7457 by setting said handle axially in any angular position 2,757,626 8/56 Fujita 112-158 thereof. 3,034,461 3/62 Urscheler 112-158 3,060,875 10/62 Iida 112-158 References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 12,764 of 1906 Great Britain.

215,699 5/79 Warnack 112-158 225199 3/80 Smith 112-458 JORDAN FRANKLIN, Primary Examiner.

709,310 9/02 Eves 112-158 F 1 611 372 12/2 Rader 112 15 X 10 DAVID J. WILLlAMOWSKY, ROBERT SLOAN, 2,002,657 5/ 35 Correll 74-57 Examine- 2,3'78,534 6/45 Beyer 112-158 

1. A ZIGZAG SEWING MACHINE HAVING A HOLLOW FRAME, A DRIVE SHAFT JOURNALLED IN SAID FRAME, A LONGITUDINALLY RECIPROCABLE AND LATERALLY SWINGABLE NEEDLE-BAR CARRIED BY SAID FRAME, EXTERIOR HANDLE MEANS ON SAID FRAME, AND A DEVICE WITHIN SAID FRAME FOR IMPARTING A VARIABLE LATERAL MOTION TO SAID NEEDLE-BAR, SAID DEVICE COMPRISING A CAM DRIVEN BY SAID SHAFT, A SWING-ARM DRIVEN BY SAID CAM AND HAVING A PIVOT AXLE AND A PLURALITY OF ADJACENT, ALTERNATIVE SLIDE-GUIDES WHICH DIVERGE TOWARDS THE PIVOT AXLE OF SAID SWING-ARM FROM A TRANSFER POSITION AT A DISTANCE THEREFROM AND IN A PLANE PERPENDICULAR TO SAID AXLE, AND A GUIDE FOLLOWER CONNECTED TO SAID NEEDLE-BAR AND ADJUSTABLE ALONG ANY OF SAID SLIDE-GUIDES FOR VARYING THE AMPLITUDE OF THE SWINGING MOTION OF THE NEEDLE-BAR AND ADJUSTABLE IN THE DIRECTION OF SAID PIVOT AXLE WHEN IN SAID 